在启用 Identity/Auth 的 EF Core 中播种数据时出现问题 .Net 5

Question

我已经使用 .net 5 和 React 模板创建了一个 ASP.NET 核心 Web 应用程序，并在 VS 向导中启用了身份验证。为 dbContext 创建的代码是这样的：

public class ApplicationDbContext : ApiAuthorizationDbContext<ApplicationUser>
  {
    public ApplicationDbContext(
        DbContextOptions options,
        IOptions<OperationalStoreOptions> operationalStoreOptions) : base(options, operationalStoreOptions)
    {
    }

我想在我从 Program.cs 调用的 seedData 方法中访问此 dbContext，如下所示：

var host = CreateHostBuilder(args).Build();
using (var scope = host.Services.CreateScope())
{
   var services = scope.ServiceProvider;
   try { SeedData.Initialize(services); } ...

当我尝试在 SeedData / Initialize 中获取对我的 Context 的引用时，我得到一个空引用错误，因为在如下实例化 DbContextOptions 时缺少构造函数的第二个参数（null 显然是错误的，但我不不知道我应该传递什么）

public static class SeedData
{
    public static void Initialize(IServiceProvider serviceProvider)
    {
        using ApplicationDbContext context = new ApplicationDbContext(
            serviceProvider.GetRequiredService<
                DbContextOptions<ApplicationDbContext>>(),null);

Answer 1

试试这个：

首先，您必须创建范围并从 program.cs 中获取需要的服务（ApplicationUser 继承自 IdentityUser ）。

 public static void Main(string[] args)
{
   var host = CreateHostBuilder(args).Build();

   using (var scope = host.Services.CreateScope())
   {
       var services = scope.ServiceProvider;

       var userManager = services.GetRequiredService<UserManager<ApplicationUser>>();

       ApplicationDbContextSeed.SeedDefaultUserAsync(userManager)
         .GetAwaiter().GetResult(;
   }

   host.Run();

}

接下来您必须在播种中创建静态播种方法 class 例如：

public class ApplicationDbContextSeed
{
    public static async Task SeedDefaultUserAsync(UserManager<ApplicationUser> userManager)
    {
        var user = new ApplicationUser()
        {
            Email = "email",
            UserName = "username",
        };

        await userManager.CreateAsync(user, "password");

   }
}

您也可以在此 class

中播种您的数据库

public static async Task SeedSampleDataAsync(ApplicationDbContext context)
{
            // Seed, if necessary
            if (!context.TodoLists.Any())
            {
                context.TodoLists.Add(new TodoList
                {
                    Title = "Shopping",
                    Items =
                    {
                        new TodoItem { Title = "Apples", Done = true },
                        new TodoItem { Title = "Milk", Done = true },
                        new TodoItem { Title = "Bread", Done = true },
                        new TodoItem { Title = "Toilet paper" },
                        new TodoItem { Title = "Pasta" },
                        new TodoItem { Title = "Tissues" },
                        new TodoItem { Title = "Tuna" },
                        new TodoItem { Title = "Water" }
                    }
                });

                await context.SaveChangesAsync();
            }
}

最后在program.cs

中调用这个方法

 public static void Main(string[] args)
{
   var host = CreateHostBuilder(args).Build();

   using (var scope = host.Services.CreateScope())
   {
       var services = scope.ServiceProvider;

       var userManager = services.GetRequiredService<UserManager<ApplicationUser>>();

       ApplicationDbContextSeed.SeedDefaultUserAsync(userManager)
         .GetAwaiter().GetResult(;

       var context = services.GetRequiredService<ApplicationDbContext>();

       await ApplicationDbContextSeed.SeedSampleDataAsync(context);
   }

   host.Run();

}

在启用 Identity/Auth 的 EF Core 中播种数据时出现问题 .Net 5

Problem Seeding Data in EF Core with Identity/Auth Enabled .Net 5

.net

asp.net-web-api

asp.net-core

.net-5